Feeler head for bore gauges



Oct. 11, 1949. A,E|SE1 E 2,484,697

FEELER HEAD FOR BORE GAUGES Filed April 2, 1945 4l 43 4 7 o 43 nventor Cttornegs Patented Oct. 11, 1949 UNITED sTATEs PATENT OFFICE FEELER HEAD'FQR BORE GAUGES Andrew Eisele, Detroit, Mich.

Application April 2, 1945, Serial No. 586,096

The present invention relates to improvements in gauges and more particularly, to gauges for testing and checking internal dimensions or diamters of various parts and work pieces.

The primary object of the invention is to pro'- vide va gauge having a feeler head so constructed and arranged as to facilitate the measurement of internal diametrical dimensions of relatively small work pieces with the ieeler contacts and associated mechanism constructed and contained in said feeler head in such a manner as to occupy a minimum amount of space.

Another object of the invention is to provide a gauge of the above-mentioned type with a pair of centering contact pins connected at their inner ends by means of an arcuately curved bridge member to provide suicient space for the inner end of the feeler contact and motion transmitting rod associated therewith, whereby said feeler contact as well as the centering contact pins may be arranged in closely spaced positions and yet provide a gauge which is extremely ac'- curate and precise.

Another object of the invention is to provide a gauge of the above-mentioned type in which the feeler head is formed spherical to allow rocking of said gauge withn'predetermined angular distances to thereby aid in determining a lcor'- rect check or reading of the gauge when measuring the internal diameter of work pieces of relatively small size and dimensions.

Another object of the invention is to provide a gauge for measuring internal diameters rof work pieces which is extremely accurate, has a high degree of precision and is compactly constructed to facilitate the checking vand testing vof relatively small bores and openings in variou work pieces.

Other objects and advantages of the inventio will become apparent during the course of the following description of the accompanying drawing,wherein:

Figure 1 is a side elevational view of the gauge embodying the invention, illustrating a portion broken away and partly in section to show the manner in which the feeler head is constructed and arranged;

Figure 2 is 'a horizontal cross-sectional view taken on line 2-2 of Figure 1, looking in the direction of the arrows and illustrating the shape of the centering pin connecting bridge and the manner of attaching the centering pins to the ends thereof;

Figure 3 is a vertical cross-sectional view taken on line 3--3 of Figure 2 looking in the direction 3 Claims. (Cl. SSL-178) of the arrows and showing the manner in which the feeler contact is disposed with its inner end 1n engagement with a iiattened portion of a `motion-transmitting rod therefor;

Figure 4 is a vertical cross-sectional view taken on line 4-4 of Figure 3 looking in the direction of the Varrows and illustrating the manner in which the centering pins are yieldingly urged outwardly of the feeler head;

Figure 5 is a top elevational view of the centering pin connecting bridge showing the general shape and contour thereof; and

Figure 6 is a side elevational view of the centering pins and connecting bridge, showing the 'manner in which the centering pins are connected to the ends of said bridge member.

In the drawing, the reference character 5 will generally be employed to represent a tubular shaft portion including a sleeve 6 having a bore I slightlyv enlarged at one end as at 8.

4Secured to one end of the tubular shank 5 is a hand grip 9 having gripping portions I9 and II for receiving the fingers of the user. A bore I3 is formed in the hand grip 9 for receiving one end of the tubular shaft 5 and is adapted to be held in place by set screws or the like as at I4. The bore I3 communicates with the bore I5 extending at right angles thereto by means of a cutaway portion I6, and received in the bore I5 is the tubular support I1 of rva dial type indicating gauge I8. A series of graduations and graduation markings I9 are formed on the dial 20 of said indicator gauge and a pointer ZI is mounted on a shaft 22 for registry with said indicating and graduation markings I9. The handle grip 9 is split rearwardly from the bore I5 for a portion of its Width so that a clamping screw 23 may cause contraction of the bore I5 and thereby tightly grip the tubular portion I1 of the dial indicator and hold the samein position. A plunger 24 is slidably mounted in the tubular portion I1 of the dial indicator and is connected to the shaft 22 in such a manner as to cause rotation of said shaft a slight amount when the plunger 24 is reciprocated.

Extending through the tubular shaft 5 is a motion-transmitting rod 25'which has one end reduced and flattened as at 26 for engaging the plunger 24. The other end is similarly flattened as at 21 and projects beyond the outer end of said tubular shank v5. The flattened portionsA 26 and 21 are arranged at an angle relative to one another about the axis of the motion-transmit; ting rod 25 in such a manner that slight rotaition of the flattened end portion 21 about the axis of the rod 25 will give a reading on the dial type indicator I8.

Supported on the free end of the tubular shank is a gauge head, including a spherically shaped body portion 28 and the radially extending projection 29 slightly reduced in diameter as at 30 for being slidably received in the bore 8 of the tubular shank 5. The spherically shaped outer portion l28 'is flattened' as ati3l and' is provided with an"en1arged bore 32 forming a chamber into which the flattened end 2l of the motiontransmitting rod Z5 is adapted to project after passing through a bore l33 inrthetubulanextension 29. The bore :'32 is slightly enlarged as at 34 for receiving a ciosure plug.352-.vvhichixis adapted to be frictionally heldiny place.. and may be forced into position by a presst. 'The closure plate is threaded as at `3l for receivingian adjustable contact 33 yand a locking nut 39 is .threaded on the contact toretain the samaina :predeterminedadjusted position.

Thespherical body portion 28 .of the vfeeler head is provided .Witha radially., extending .bore .40.;at rig-htangles to the radially extending. .bore l33.. for Vreceiving a movable feeler contact 4| whichhas an enlarged head portion 42 for being fengagedby the flattened portion 21 of amotiontransmitting rod 25 so that reciprocating motion impartedto the rounded end`43 of .the movable feeler contact 4| Will rotate said motion-transmitting rod 25 about its. axis and cause reciprocation of .theplunger'24 `a Vcorresponding amount which will. be indicatedon the dial type .indicator I8. A coil spring 44 encircles thereduced portion of the vplunger 24 lso .as topplace the `.plunger .-undertension and cause thesame tobe rotated ,ina -predetermined direction.

.Arranged inparallel relation with the bore 40 on each side thereof isa pair-of tangentially. ex- -vtending bores lli which likewise communicate with .the enlarged chamber 32 for. receiving mov- .able centering pins or contacts'46. The. ends of the centeringpins are. rounded'as, at 41.50 .as -to contactually engageA .the curvature .,of..a ibore y.or the. like .on..both sides .of the .movable eeler l.Contact 4I. The inner ends ofthecentering pins or contacts 46 areconnected by ,anfarcuately shaped` bridgev piece 48 by .being weldedor othervrevise. secured ,thereto .andnsaid .bridge .,-pieoeeis `arranged -to encircle. theenlarged. head 42 of ..the .movable feeler contact 4 :aswell .as theflattened `end 21 ofthe motion-transmitting rod..25. Y.The .closure plug 35 isprovided witha pair llof. recesses I4.8 `in -opposed relation tothe-.innerfendof .the .centering or contactpins .-46 for receivingf coil :springs lltherein, .whichare .arranged sozthat .they willl engage the ends of the bridgepiece 148 andyieldingly urge the.centeringforicontact pins-46 ina projected position.

Operation of the Vinvention In determining the,internalvfdiameterof. abore ,.-B ina work piece W, the feeler head is inserted :in

.the bore B so that the movable feelercontactlll and adjustable contact 38 are in contactual.-` en- ,gagement with the diametrical fportionsofsaid `ibore- B. Thecentering pins 46 engagethebore :B1 on opposite sides of the feeler contact-4| to. retain the same and the feeler :head in. a: centered position. `As the feeler headxismoved backrand forthin theboreB, .any irregularities inthe sur- Aface therein will be indicatedzon the .dialt type indicator i8. .Bywobblingthe handgrip 9;'slight-f flythe feelerV contact 4 l tand; adj ustable; contact 'A ne 38 may be brought into such a position as to give an exact reading of the inner diameter of the bore B in the work piece W.

It is to be understood that the form of the 5 invention herewith shown and described is to be taken as a preferred embodiment of the same and that various changes may be made in the shape, size and arrangement of parts without departing from the spirit of the invention or the fscopef the subjined claims.'

"What I'claim is:

1. In a bore gauge, a tubular shank having one eend adapted to be connected to a dial indicator, c yaggauge-.head mounted on the other end of said shank, said head having a cavity therein and cavity and the other end projecting from said `shank for connection to said indicator, amovable .-feeler contact pin extending outward through another of Asaid bores with its innerend engaging the endof. said .motion-transmitting rod,..a..pa r

v: of centering pins .mounted ina pair of said bores :one on each sideof the ymovable contact pin, an aapproximately -Usha-ped bridge member inter- .connectingsaid centering pins and partially. en'- -circling the end of-.said motion-transmitting rod,

a spring in. said head yieldingly engaging. said bridge .member and uring said centering pins outwardly of said head, anda stationarycontactpin projecting outwardly. from said head inlthe .op- ,posite direction from said .movable measurngpin .and in alignment therewith, the longitudinalaxis offsaid motion-transmitting rod and said bridge member being disposed substantially in a common plane, with the end of said rod projecting Ainto :the open side of said bridgemember between the ,'ends thereof.

; 2.V In a bore gauge, a tubular shank having-one endadapted tobe connected to a dial indicator, a partially spherical gauge headmounted on` the yother-end-of said shank, said head havinga cavity 445 .therein and a plurality of bores extendingfrom -said:.shank for-":connectionl to* said indicator, fa

movable feeler ,Contact pin :extending :outward .'.throughianother ofk said bores withits inner. end engaging i the end of said: motion-transmitting frod, a pair` of centeringqpins mountedinfaiapair 'ofzsaid bores-.one oneeachjside ofthe vmovable 'contact pin, an i approximatelyy U ishaped bridge :member :interconnecting said tcentering pinsiand partially encircling the end of said motionetransmitting rod,.\a:` spring. in saidihead yieldinglyeni60 -iga'gng saidnbridge 'member and'urgingaid centering pins outwardlyoi` said head,` and a` station-f ary contact pin projecting outwardlyfrom'said rhead intheopposite direction from said :movable vmeasuring pin: and in alignment therewith, .'Zthe `65 :longitudinal axis .ofzsaid 'motionetransmittingrod .arid said bridge membersbeing disposed substantially in a common plane, with the"en`d:.of said rod: projectingr intoL the lopen fside of saidrbridge memberfbetween the ends thereof; said bridge 7,0 member l and"said"motion-transmitting rodE being fdisposed substantially `in va .fdiametralrplane of `saidi'parti'allyr sphericalgaugei head. i

3. In a bore gauge, a tubular shankfhavingone endfadapted to be vconnected. to; afdialijndicator,

$5 .asgauge headfmountedi ony .thethera'end of'said shank, said head having a cavity therein and a plurality of bores extending from said cavity to the outside of said head, a motion-transmtting rod extending through said shank with one end projecting through one of said bores into said cavity and the other end projecting from said shank for connection to said indicator, a movable feeler contact pin extending outward through another of said bores with its inner end engaging the end of said motion-transmitting rod, a pair of centering pins mounted in a pair of said bores one on each side of the movable contact pin, an approximately U-shaped bridge member interconnecting said centering pins and partially encircling the end of said motion-transmitting rod, a pair of laterally-spaced spiral springs in said head yieldingly engaging said bridge member and urging said centering pins outwardly of said head, and a stationary contact pin projecting outwardly from said head in the opposite direction from said movable measuring pin and in alignment therewith, the longitudinal axis of said motiontransmitting rod and said bridge member being disposed substantially in a common plane, with the end of said rod projecting into the open side of said bridge member between the ends thereof, said springs being disposed substantially co-axial with said centering pins and engaging the ends of said bridge member.

ANDREW EISELE.

REFERENCES CITED The following references are of record in the le of this patent: l

UNITED STATES PATENTS 2,385,157 Nilsson et al. Sept. 18, 1945 

